If you are planning to build a fast but quiet system with low power consumption, then Intel may offer you a variety of LGA1155 processors with 45 W or 35 W TDP. But does cutting their power consumption in half bring any additional limitations? Let’s find out!

Conclusion

Sandy Bridge microarchitecture is amazingly diverse. We have already admired the high performance of processors based on it many time, and today we saw clearly that it is also a perfect fit for products to be used in quiet, compact and energy-efficient systems. However, the T-series processors discussed in our today’s article revealed a number of unique peculiarities, which aren’t mentioned anywhere in the official specs but can change your perception of these products.

Take a look at their power consumption. Although I-series processors have half the TDP of the regular CPUs, it doesn’t at all mean that in reality they only consume half the power. Firstly, energy-efficient processors get very close to their TDP threshold, while regular CPUs can often consume less power and dissipate less heat than their TDP implies. Therefore, the actual difference in practical power consumption between T and non-T processors of the same class is never that significant. Secondly, we can really see a serious difference in practical power consumption between energy-efficient and regular processors only in a limited number of usage scenarios, while most of the time their power appetites are very close. In fact, T-series processors show their true energy-efficiency only under heavy multi-threaded load. In idle mode, under single-threaded load or during high GPU utilization, T-series processors do not offer any noticeable advantages in the power aspect.

All this means that it doesn’t make sense to use energy-efficient Sandy Bridge modifications just for the sake of saving some power. Since in real life the processors are usually loaded sporadically, T-series won’t bring you power bill down a lot.

These processors, however, offer you another indisputable advantage. If you need to limit the maximum power consumption and heat dissipation of your system, for example, if your system is assembled inside a case that can only accommodate a low-efficiency cooling system, or if you are using a low-capacity power supply unit. In this case Intel T-series processors may be truly irreplaceable.

However, power consumption and heat dissipation limitations do affect the performance quite significantly. In terms of peak computational performance, CPUs with 45 W and 35 W TDP on average work about 15-20% slower than the regular CPUs of the same class and price. However, in case of Core i5-2500T and Core i5-2390T, they will only fall that far behind under serious multi-threaded load. In all other cases, they will get a serious boost from their aggressive Turbo Boost technology. Another two T-series CPUs, Core i3-2100T and Pentium G620T, do not support Turbo Boost and fall far behind the fully-functional models in all cases.

But things aren’t bad after all. Core i5-2500T and Core i5-2390T are two unique products, which in many aspects can be superior to regular 65 and 95 W processors. Namely, Core i5-2500T has the fastest modification of Intel HD Graphics 2000 core, which makes this processor faster than any of its LGA1155 brothers in 3D and with QuickSync technology activated. As for Core i5-2390T, it can actually be called the fastest dual-core desktop processor on Sandy Bridge microarchitecture out there.

As a result, we can conclude that T-series processors, especially those from Core i5 family, are very interesting products, which often offer very unique advantages. However, overall, Core i5-2500T, Core i5-2390T, Core i3-2100T and Pentium G620T are niche products, which may be interesting only in a limited number of practical applications. It is also important to remember that in many cases T-series processors may be replaced by 65 W Pentium CPUs, which often consume the same or even less power than 45 and 35 W Core i5 and Core i3 products.

In other words, choosing the best CPU for an energy-efficient system is not easy and there is no single recipe for success. Of course, Intel’s options offering special processor modifications with lower thermal envelopes are worth considering, but we can’t guarantee that they will be the only good choice in each particular case.